Double-twist spindle

ABSTRACT

A double-twist spindle for doubling a yarn in which an integral shaft and rotor rotate with respect to a stator, which is magnetically held against rotation and carries a spool of yarn. An axial and a radial passage in the shaft and rotor respectively join in the rotor at the location of a removable, normally fixed yarn guide.

0 United States Patent 51 3,640,060 Boyer 5] Feb. 8, 1972 [54] DOUBLE-TWIST SPINDLE 2,640,310 6/1953 Roberts ..57/58.76 X [72] I t J Bo S t F 2,684,566 7/1954 Roberts am 2,827,756 3/1958 Kellogg et al. [73] Assignee: Societe Rhodiaceta, Paris, France 3,177,643 4/1965 Halleux et al ..57/58.86 [22] Filed: Dec. 31, 1969 FOREIGN PATENTS OR APPLICATIONS [21] Appl. No.: 889,646 571,487 10/1958 Belgium ...57/58.76 725,283 3/1955 Great Britain ..57/58.86 [30] Foreign Application Pnonty Data Primary ExaminerDonald E. Watkins Dec. 31, 1968 France ..50,893 Attorney-Stevens, Davis, Miller & Mosher [52] U.S.Cl ..57/58.84,57/58.86 [57] ABSTRACT A double-twist spindle for doubling a yarn in which an integral 5. g shaft and rotor rotate with respect to a stator, which is magnetically held against rotation and carries a spool of yarn. An axial and a radial passage in the shaft and rotor respectively [56] References cued join in the rotor at the location of a removable, normally fixed UNITED STATES PATENTS y guide- 2,559,735 7/1951 Roberts ..57/58.76 X 5 Claims, 2 Drawing Figures PATENIEDFEB 8|972 '3 640 060 JACQUES BOYER INVENTOR A TTORNE YS DOUBLE-TWIST SPINDLE The present invention relates to a double-twist spindle for doubling filamentary materials, especially yarns produced from continuous filaments or discontinuous fibers. In the remainder of this specification, all the said filamentary materials will be described by the single term yam.

Doubling by double twist generally applies a high tension to the yarn, which increases with the speed and very rapidly becomes prohibitive, particularly in with fine gauge yarns.

This tension is furthermore not constant and its irregularities cause bad distribution of twist along the yarn. It is known that such a defect seriously restricts the use of the yarn because it manifests itself in an unaesthetic appearance of the knitted fabric or by stripes ona woven fabric after dyeing.

According to the present invention there is provided a double twist spindle for doubling a yarn comprising a single-piece shaft rotatable about its axis, a rotor at least in part integral with said shaft and rotatable therewith, a yarn accumulating surface on the periphery of the rotor, an axial bore in the shaft extending into the rotor and joined to a radial bore in the rotor extending to the periphery thereof a fixed yarn guide being positioned at the junction of the axial and radial bores, a stator mounted on the shaft and magnetic means to prevent rotation of the stator upon rotation of the rotor and shaft.

Since the spindle includes a single-piece integral with the rotor, the rotating elements can be centered very accurately and provides excellent dynamic equilibrium, permitting high speeds of rotation of the spindle.

On the part of the shaft which will by convention be called the upper part, although the spindle according to the present invention can be used equally well in a horizontal or vertical position or in any other position of the axis of the shaft, the stator of the spindle is mounted in a manner which isin itself known, and this stator can carry the bobbin which is to be twisted and a yarn-tensioning device. Any type of tensioning device can be used but preferably a tensioning device with magnetic rollers 'is used because of its low inertia and the precision of the tensionit applies to the yarn.

AT the intersection of the axial and radial bores or, in other words, at the change in direction of the continuous passage which they form, is located a fixed yarn guide which guides the yarn to be twisted from the axis of the axial bore to the axis of the radial bore.

The yarn guide may be mounted in a transverse passage and preferably exhibits a surface of revolution, at least in the part where it is in contact with the yarn. The said part exhibits a well-defined surface condition which by friction imparts a defined amplification of tension to a given yarn which is under defined tension. Of course the friction effect is in practice reduced to the lowest possible value, for example by using a guide of which the surface is polished.

The yarn guide is preferably removable so that it can easily and rapidly be replaced in case of wear or soiling or in order to suit its surface condition better to the twisting of a yam of different characteristics.

The path of the yarn in the shaft and in the rotor is no only determined by the front yarn guide in the rotor but also by guides, preferably in the form of eyelets, at the inlet, at the outlet and in the zone of the path from the shaft to the rotor. The path of the yarn is thus well defined from where it issues from the tensioning device, which gives it a constant tension, until it issues into the open air at the periphery of the rotor and advantageously in a straight line with the outer end of the radial bore.

At the periphery of the rotor, a yarn accumulation device is arranged in the form of a circular collar exhibiting a flared-out part of frustoconical or bowl shape. The external diameter of the accumulation device can be less than, equal to or greater than the external diameter of the stator.

The stator is prevented from rotating by magnetic means, preferably by permanent magnets of which some are fixed to the lower part of the stator and the others to the fixed support of the shaft. The magnets are distributed on either side of the rotor, preferably in the radial part thereof and advantageously in a zone where the rotor is thinned down so as to reduce the gap but preferably in a zone where the yarn to be twisted is guided in the radial bore, which eliminates any risk of the yarn catching on the magnets. The part of the rotor which is arranged in the gap is advantageously made of an insulating material, so as to avoid a dissipation of energy by Foucault currents in this part.

The present invention will be better understood from the following description, given merely by way of example, reference being made to the accompanying drawing, in which:

FIG. 1 is a side elevation in section of one embodiment of spindle according to the invention and FIG. 2 is a plan view of the yarn guide of FIG. 1, shown removed from the spindle.

The spindle shown in the drawing includes a single-piece shaft I mounted in ball bearings 3 on a support 2, whichis rigidly fixed to the framework of the machine by means which are not shown and is rotated by a drive belt 4 in a conventional manner.

In its middle, the shaft is provided with a shoulder on which rests the radially extending portion of a rotor 5, which is kept in position by three screws 6 of which only one is shown in FIG. 1. In its radially extending portion, the rotor is provided with a radial bore 7, which also extends radially into the shaft up to the level of the axis of rotation, where it joins and is then axially extended by the passage 8 up to the end of the shaft which in accordance with the usage indicated above will be called the upper end.

In the zone where the bores 7 and 8 intersect, the shaft I is formed with a transverse passage or recess 9A in which a ceramic yarn guide 9 is fixed. The central part of the guide (see FIG. 2), with which the yarn comes into contact, is a surface of revolution and is eccentric relative to the ends of the guide, the diameter of which corresponds to that of the bored passage 9A of the shaft 1. This central part forms the bottom of a V-shaped throat which is open at 90. The guide 9 is kept in place in the shaft by a clip which is not shown, so that the surface of revolution in contact with the yarn is essentially tangential to the axis of each of the bores 7 and 8.

The stator 10, made of a molded plastic, is mounted on the shaft 1 by ball bearings 11, via a vibration-damping element. It carries the bobbin 12 mounted on its support, against which rests a holder 13 carrying a yarn-tensioning device 14 with magnetic rollers, arranged along the axis of the spindle at a short distance above the upper end of the shaft. A fixed sheet metal cover 15 and a transparent lid 16 are also mounted on the stator. Thiscover is removable to allow the bobbin to be placed in position. It allows the balloon formed by the yarn upstream from the tensioning device and downstream from the rotor to be well separated, and thus to unwind bobbins regardless of the direction of winding of the yam on these.

The base of the stator has an annular groove in which are located four magnets 17, located opposite to four fixed magnets 18 on the upper part of the framework 2, this part preferably being made of a nonmagnetic material. The magnets are inserted in apertures of the stator 10 and of the upper part of the support 2, so that their opposite faces are flush with the opposite parts of the annular groove of the stator and of the framework 2, and so that their opposite poles face one another. The gap thus produced may, for example be 7 mm.

The rotor 5 consists of a plastic disc having a collar the thickness of which is reduced to 5 mm. at the level of the gap and provided, at its periphery, with a collar 19 made of aluminum alloy for accumulating the yarn, and which is to the plastic disc attached by six screws 20, of which only one is shown. The radial channel 7 of the rotor opens out, through an eyelet 21, onto the cylindrical part of the collar 19, which is surmounted by a truncated cone flared-out section which allows the yarn to be wound up before forming the balloon. The eyelet 21, as well as the eyelets 22 and 23 located in the part of the yarn at the inlet and outlet of the shaft, guide the yarn from the axis of the bore through the spindle.

cylindrical sleeve 100 mm. high, of external diameter 210 mm.

and internal diameter 75 mm. The cover used with this bobbin is 78 mm. high.

Using a cover 15 which is 150 mm. high, the above spindle makes it possible to twist a cake of viscose yarn 180 mm. high, of slightly conical shape, of which the respective lower and upper ends have an external diameter of 190 and [80 mm. respectively, this cake 180 mm. respectively, this cake being supported by a plastic sleeve, again conical in shape and of 120 mm. diameter at the level of the lower end of the cake and 1 10 mm. diameter at the level of the upper end, which ensures the rigidity of this cake.

The spindle of the present invention is applicable to twisting bobbins of very varied types and sizes, and especially large bobbins such as those obtained by high-speed continuous winding up of synthetic filaments following their extrusion, as well as bobbins obtained by winding or twisting yarns formed from natural or synthetic continuous filaments or spun yarns of discontinuous fibers.

I claim:

1. A double-twist spindle for doubling a yarn and comprising in combination:

a. a single piece shaft rotatable about its axis;

b. a rotor at least in part integral with said shaft and rotatable therewith; c. a periphery to said rotor; d. a yam-accumulating surface on the periphery of the rotor, said yarn-accumulating surface being adapted to accumulate yarn on said rotor;

e. means defining an axial bore in said shaft extending into said rotor;

f. means defining a radial bore in said rotor extending the full radial distance between said axial bore and said yamaccumulating surface;

g. a fixed yarn guide at the junction of said radial and axial bore;

h. a stator mounted on said shaft; and

i. magnetic means effective to prevent rotation of said stator upon rotation of said rotor and shaft.

2. A double-twist spindle as claimed in claim 1, and further comprising a radially extending portion to said rotor in which said radial bore is formed, and wherein said magnetic means are located adjacent the periphery of said rotor on both axial sides of said radial portion.

3. A double-twist spindle as claimed in claim 1, wherein said fixed guide is removably mounted in said rotor.

4. A double-twist spindle as claimed in claim 3, and further including a transverse passage in said rotor, said fixed guide being located in said transverse passage.

5. A double-twist spindle as claimed in claim 4, wherein said fixed yarn guide comprises a substantially cylindrical member having a central circumferential groove defined therein, disposed eccentrically of the member axis, whereby the axes of the axial bore and radial bore in the rotor are tangential to the lower surface of the groove. 

1. A double-twist spindle for doubling a yarn and comprising in combination: a. a single piece shaft rotatable about its axis; b. a rotor at least in part integral with said shaft and rotatable therewith; c. a periphery to said rotor; d. a yarn-accumulating surface on the periphery of the rotor, said yarn-accumulating surface being adapted to accumulate yarn on said rotor; e. means defining an axial bore in said shaft extending into said rotor; f. means defining a radial bore in said rotor extending the full radial distance between said axial bore and said yarnaccumulating surface; g. a fixed yarn guide at the junction of said radial and axial bore; h. a stator mounted on said shaft; and i. magnetic means effective to prevEnt rotation of said stator upon rotation of said rotor and shaft.
 2. A double-twist spindle as claimed in claim 1, and further comprising a radially extending portion to said rotor in which said radial bore is formed, and wherein said magnetic means are located adjacent the periphery of said rotor on both axial sides of said radial portion.
 3. A double-twist spindle as claimed in claim 1, wherein said fixed guide is removably mounted in said rotor.
 4. A double-twist spindle as claimed in claim 3, and further including a transverse passage in said rotor, said fixed guide being located in said transverse passage.
 5. A double-twist spindle as claimed in claim 4, wherein said fixed yarn guide comprises a substantially cylindrical member having a central circumferential groove defined therein, disposed eccentrically of the member axis, whereby the axes of the axial bore and radial bore in the rotor are tangential to the lower surface of the groove. 